Room Treatment Advice

[Hari Iyer]

72" from front wall?.. That is 6ft.. What are your room dimensions?.. Where is your listening position in the room ?..

Length- 17 feet, Width- 9 5 feet ( opens to L shape dinning area), Height - 8.5feet+ 0.5 feet false ceiling.
Listening position 9 feet away from speaker, current final position for speaker is 4 feet 4" from front wall.
2 feet distance behind my back opens to a sliding window
Speakers from the driver center are 8" away from the side wall

 

[Hari Iyer]

A picture speaks more than a 1000 words

 

[Hari Iyer]

Missed one most important aspect of my speaker placement - The ratio of the distance between the centers of both the speakers and the front wall is an golden ratio.
Distance between two speakers are 87.5" and distance from front wall is 52.5".
Ratio is 0.6.

 

[elangoas]

Length- 17 feet, Width- 9 5 feet ( opens to L shape dinning area), Height - 8.5feet+ 0.5 feet false ceiling.
Listening position 9 feet away from speaker, current final position for speaker is 4 feet 4" from front wall.
2 feet distance behind my back opens to a sliding window
Speakers from the driver center are 8" away from the side wall

Keeping the speaker closer to the boundary, is said to shift the SBIR to a higher freq - http://arqen.com/acoustics-101/speaker-placement-boundary-interference/

Am sure you must have tried closer (witnin 6 inches from the wall behind the speaker) positioning.. Any reason you didn't prefer that positioning?.. Was the freq response more problematic there?..

 

[Hari Iyer]

Keeping the speaker closer to the boundary, is said to shift the SBIR to a higher freq - http://arqen.com/acoustics-101/speaker-placement-boundary-interference/

Am sure you must have tried closer (witnin 6 inches from the wall behind the speaker) positioning.. Any reason you didn't prefer that positioning?.. Was the freq response more problematic there?..

elangoas, i have never tried placing the speakers 6" from the wall behind the speaker - because i dont have space, and being a OB speaker they need some decent space behind them to get the "8" dipole pattern.

if you observe the final speaker arrangement which is 52" from the front fall. This gives a wavelength of 257Hz. Now half wavelength is 128Hz. You can see now that at 128Hz there is adding of the waves and there is no dip. The 1/4th wavelength is 64Hz where cancellation would occur. You can see there is a minor dip in the response at around that frequency. So my placement agrees with the link which you have send.

 

[sound_cycle]

@Hari Iyer That was a top tip - getting very close to the wall. I am right up against the side wall as close as the panel can get. I moved the panels around the about 4 sq feet that I can have them in to get the REW plots for the two speakers as near identical as possible while keeping them symmetrical . And there was one more variable, my LP. That exercise took forever. And then figuring out the reflections and squashing them. About 6 hours of fiddling.

The results were worth it. I have a nice lovely image with the phantom centre at eye level (that last was also because of getting 16 sq ft of foam on the back wall). There is a whole lot of detail that is now clearly audible.

I still have not figured out how to post the pics I will figure out and do that.

I have to get the tube traps to absorb in that ~50 region to eliminate that null. But for now this is very listenable. And I am quite pleased with the sound, for now at any rate.

Thanks

https://photos.app.goo.gl/a6NE9SxhynQJ5r7dA panels next to side wall

https://photos.app.goo.gl/mSvA4k7fJ21UagS39 All SPL

https://photos.app.goo.gl/Q1Wr6uxLHbWqaf7u8 waterfall

https://photos.app.goo.gl/py4R2pVvLnU1APkn6 spectrogram

https://photos.app.goo.gl/mjxgvgJDJhYiV51v5 ETC L
https://photos.app.goo.gl/rztF6BAQSLABM8NQ9 ETC R

https://photos.app.goo.gl/yYuVKmpm9iKC7MpM7 the final config





ciao
gr

 

[elangoas]

I still have not figured out how to post the pics I will figure out and do that.

Use imgur, external image hosting site.. It is free & easy to upload images.. Once uploaded in that site, copy the BB Code of that image and paste it in your post.. This will show up the full image on your post, than accessing the links thru google Photos..

Any reason why you haven't measured the combined response of L + R speakers?..

I have to get the tube traps to absorb in that ~50 region to eliminate that null. But for now this is very listenable. And I am quite pleased with the sound, for now at any rate.

Plz share some info on the proposed tube trap.. Diameter, how tall, hollow width etc..

 

[sound_cycle]

Any reason why you haven't measured the combined response of L + R speakers?..
<snip>Plz share some info on the proposed tube trap.. Diameter, how tall, hollow width etc..

The SPL waterfall & spectrum plots are for both speakers. The ETC is for one at a time, one of the uses is to identify and maybe squash reflections, and therefore one at a time. BTW you will see that there is no significant "floor" reflection, there is some from the ceiling.

I have so far have had no success with finding any formulae for the tube traps. The ASC site says that their 11.6 inch dia traps are good to 70 hz. There are other designs which use a limp membrane inside the tube to increase efficiency/ be useful at lower frequencies. I figure I would need to match the height of my source so 6 - 8 feet. There is one listed on Auralexchange for about 8K, 32K for 40 kg of traps. A powerful motivation for DIY But I know I have to tackle that backwave for a huge gain in SQ.

ciao
gr

 

[elangoas]

There is one listed on Auralexchange for about 8K, 32K for 40 kg of traps. A powerful motivation for DIY But I know I have to tackle that backwave for a huge gain in SQ.

32K seems expensive.. DIY would be economical and ofc customize it your liking..

 

[Hari Iyer]

Sound cycle, good to know this. Try golden ratio placement if possible. That way you need not keep the speakers touching the wall and still get good sound stage and image.

 

[Hari Iyer]

@sound_cycle the dip at 100Hz is because the speakers are too inside the room. This can be removed by moving them a little back closer to the front wall (you have a door opening there am not sure how you can manage that). I am not much worried about the dip in the 40Hz which would not be much audible, but 100Hz is audible and needs to be addressed.

 

[sound_cycle]

@sound_cycle the dip at 100Hz is because the speakers are too inside the room. This can be removed by moving them a little back closer to the front wall (you have a door opening there am not sure how you can manage that). I am not much worried about the dip in the 40Hz which would not be much audible, but 100Hz is audible and needs to be addressed.

I think I have exhausted all arrangement / positioning based possibilities. I described the fine gridded evaluation around the final postion. I had also tried out some unlivable with impractical ones, closer to the front well, properly out almost to the middle of the room etc..

I am not sure if my brain is playing tricks on me, or I have gotten used to what I am hearing (and there is also the Dirac EQ which the REW graphs do not show) but for the moment it sounds okay. I am not saying there this no room for improvement, or that I am not open to trying out alternates, just that for a while, a couple of weeks maybe I am going to let it be.

Will update

ciao
gr

 

[sound_cycle]

The treatment I am settling on (nothing is permanently fixed yet).

Also added a power conditioner, seen far right

ciao
gr

PS: Krall sounds really really good

 

[sound_cycle]

Symmetry in an asymmetrical listening space does not lead to the best results (above pic)

Distance is one thing, toe in another. A slightly left biased image was something that irritated me for a long time. Gone now. Distance to centre of panels is exactly the same (given the limitations of laser measurement and eyeballing centre of panels, I'm OCD and lazy). But the rhs panel is toed shallower. I have a slightly nicer image and a somewhat louder bass.

Have to measure it and see if it corroborates my impression. Or trashes it.

Ciao
GR

PS nothing is fixed yet. Told ya I procrastinate with the best

 

[sound_cycle]

Hi

Happy Ugadi (and hopefully a virus free reboot).

I have the same arrangement as I had worked out a while back.

I was without Dirac for a while.

Did a careful setup today with ver2 of Dirac Live.

Imaging is now needle sharp. McEvoy is right in front centre, the shalala from Waterloo sunset is next to my right ear (that's an accidentally phase mixed recording and I use it as a test track)

Details in the highs (plinking pianos, guitars are like I have imagined them, but not heard. That last few percent is what I have to get, I think

I saved the best for the last. The bass is tight gorgeous six pack abs Delish.

Taut, sexy and lovely to listen to. So far played power of goodbye (Madonna) and I will survive (musica nuda, omg what the **** am I listening to now good, fat gobs of textured bass goodness) and dreaming of leaving (McEvoy). The bass, in across the lines. I'm very impressed.


No charge in arrangement. Only dirac2

Ciao
GR

 

[mpw]

Hi

Happy Ugadi (and hopefully a virus free reboot).

I have the same arrangement as I had worked out a while back.

I was without Dirac for a while.

Did a careful setup today with ver2 of Dirac Live.

Imaging is now needle sharp. McEvoy is right in front centre, the shalala from Waterloo sunset is next to my right ear (that's an accidentally phase mixed recording and I use it as a test track)

Details in the highs (plinking pianos, guitars are like I have imagined them, but not heard. That last few percent is what I have to get, I think

I saved the best for the last. The bass is tight gorgeous six pack abs Delish.

Taut, sexy and lovely to listen to. So far played power of goodbye (Madonna) and I will survive (musica nuda, omg what the **** am I listening to now good, fat gobs of textured bass goodness) and dreaming of leaving (McEvoy). The bass, in across the lines. I'm very impressed.


No charge in arrangement. Only dirac2

Ciao
GR

Long time

No see

 

[sound_cycle]

Long time

No see

Dabba chasing done, was actually content with the rig and listening to stuff. Lots, I have my place to myself after the inmates moved to blru.
Dirac had meanwhile put out a beta, which was a little fiddly (because Roon does not like VXT), for a while ran with no correction. This enforced break led me to d/l and reinstall and it was an ear opener !

edit: since that last pic I posted above, I now run two vidars in mono with a ghetto xlr arrangement. would have loved to get freya+ but all plans corona-ed

ciao
gr

 

[mpw]

Dabba chasing done, was actually content with the rig and listening to stuff. Lots, I have my place to myself after the inmates moved to blru.
Dirac had meanwhile put out a beta, which was a little fiddly (because Roon does not like VXT), for a while ran with no correction. This enforced break led me to d/l and reinstall and it was an ear opener !

edit: since that last pic I posted above, I now run two vidars in mono with a ghetto xlr arrangement. would have loved to get freya+ but all plans corona-ed

ciao
gr

While you were away I got myself made an 18 inch sealed sub..

 

[sound_cycle]

While you were away I got myself made an 18 inch sealed sub..

That's a nuclear sub ! will find your thread and read up.
ciao
gr